Summary

The reducing sugar content of tubers is of considerable importance in potato processing, particularly in the manufacture of chips (crisps) and pommes frites. In the work described, the reducing sugar content of 8 varieties and 19 breeding lines from the 1967 harvest and 13 varieties from the 1968 harvest was determined after the following storage treatments:

I=

at lifting.

II=

storage at 6–10°C from October to February.

III=

three weeks reconditioning at 20°C following II.

IV=

three weeks cold storage at 2°C during October/November.

V=

three weeks reconditioning at 20°C following IV.

The Luff-Schoorl method was used for sugar analysis and the percentage of reducing sugars, calculated on a fresh weight basis, scored on a scale of 10-1 (Table 1). The varieties and lines can be divided into the following five groups on the basis of their reducing sugar content (Tables 3 and 5):

Group 1:

high sugar content in I–V.

Group 2:

low sugar content in I, high content in II–V.

Group 3:

low sugar content in I–III, high content in IV and V.

Group 4:

low sugar content in I–III and V, high content in IV.

Group 5:

low sugar content in I–V.

The processing industry require the selection of varieties, particularly for the manufacture of chips (crisps), which accumulate so little sugar at storage temperatures of 4–5°C that they can be used without reconditioning.

The above classification of varieties in five groups according to their reducing sugar content offers the possibility of giving the processing industry more precise recommendations.